U.S. regulator set to approve Dow's Enlist herbicide

April 30 (Reuters) - The U.S. Environmental Protection Agency said on Wednesday that it was planning to grant approval to a new herbicide developed by Dow AgroSciences that is designed to be used with new genetically engineered corn and soybeans and combat weed resistance.

The new herbicide, dubbed Enlist Duo, contains a combination of the herbicides 2,4-D and glyphosate, and has been heavily criticized by groups who say commercialization of Enlist will harm the environment and worsen weed resistance problems.

Regulatory approval of the herbicide and crops have been delayed for more than a year after the EPA and the U.S. Department of Agriculture, which must grant approval of the crops genetically engineered to be tolerant of Enlist Duo, were inundated with pleas to reject Dow’s applications.

The USDA said in January it was prepared to grant approval and is expected to finalize that decision in the next few months.

And on Wednesday, the EPA said it too was prepared to grant approval and would accept public comments for 30 days on its decision. The EPA said it would impose requirements on Dow, including “robust monitoring and reporting to EPA,” grower education and remediation, and it would “allow EPA to take swift action to impose additional restrictions on the manufacturer and the use of the pesticide if resistance develops.”

Dow AgroSciences, a unit of Dow Chemical, developed what it calls the Enlist Weed Control System as millions of acres of farmland have become choked with weeds resistant to glyphosate, the chief ingredient in the popular Roundup herbicide sold by Dow rival Monsanto Co..

More than 86 percent of corn, soybean and cotton growers in the U.S. South and 61 percent in the U.S. Midwest reported hard-to-control weeds on their farms, according to Dow.

“Enlist Duo herbicide will help solve the weed control challenges growers are facing and will be another option to further reduce the potential for development of herbicide-resistant weeds,” said Damon Palmer, Dow’s commercial leader for the U.S. market.

Dow officials have said Enlist corn and soybeans should be on the market by 2015 - roughly two years after the initial target launch date. Enlist cotton should follow them at some point in the future, they added.

Critics say that 2,4-D and other herbicides of its class have been independently associated with deadly immune system cancers, Parkinson’s disease, endocrine disruption and reproductive problems.

“Biotechnology is taking agriculture backwards by facilitating a massive increase in use of this toxic herbicide, which formed part of Agent Orange used in Vietnam,” said Bill Freese, a science policy analyst at the Center for Food Safety, a non-profit group that has sought to block approval of the Enlist products.

Reporting by Carey Gillam; Editing by Cynthia Osterman